Devices for spectral tissue sensing and for other spectral sensing methods include a broadband light source and one or more broadband spectrometers. In practice, two of these are included because of the need to cover both the visible and the near infrared wavelength ranges. Example prior art for Spectral Tissue Sensing are disclosed in International Patent Applications WO2012/127378, WO2012/093309 and WO2013/001423. International Patent Application WO2011/132128 discloses an example where a limited number of wavelengths are used to detect water and lipid.
This Spectral Tissue Sensing has a great potential in many application areas, especially in the medical applications area. However, to become a success, both cost and form factor are of high importance. Current state of the art technology still requires systems that need to be transported on a separate cart and that involve high cost. The result is that these systems are only used in a hospital environment, where only a limited number of such devices will fit in the budget and workflow.
Document US20120226118A1 discloses an implantable sensor for sensing a substance such as glucose. The sensor comprises a photonic integrated circuit based radiation processor for spectrally processing radiation interacting with the sample.
Document US20070109550A1 discloses a system and method for detecting the optical spectrum of an optical input signal. The system includes a tunable optical filter having a microresonator that is tunable across a plurality of states and a processor. The input signal is coupled into the microresonator, which is continuously tuned across a spectral range that is narrow relative to the targeted detection range.
Document US2009/0245796 relates to the optical communications field and discloses a planar lightwave circuit that includes a substrate, a tunable filter, a demultiplexer, and an optical processor each disposed on the substrate. The tunable filter is configured to filter at least one of a bandwidth or a wavelength of a Wavelength Division Multiplexed optical input signal. The demultiplexer is connected to the tunable filter and configured to receive a filtered Wavelength Division Multiplexed optical input signal at an input and to supply one of a plurality of channels of the filtered Wavelength Division Multiplexed input signal at a respective one of a plurality of outputs. Each of the plurality of channels corresponds to one of a plurality of wavelengths of the filtered Wavelength Division Multiplexed input signal. The optical processor includes a bit-delay interferometer communicating with a respective one of the plurality of outputs of the demultiplexer. The optical processor is configured to receive one of the plurality of channels from the demultiplexer and output a plurality of demodulated optical signal components.